The invention relates to an optical fiber connector in the form of a coupling nut. More specifically, the invention relates to an optical fiber connector which receives and terminates two side-by-side optical fibers. The connector comprises a fiber nut housing which includes a spherical mirror so that the light emission from one of the side-by-side fibers is coupled into the other side-by-side fiber.
Many optical fiber connectors which optically connect one optical fiber to another are known to persons of skill in the art. In most of these connectors, the transmission core of a first optical fiber is axially aligned with that of a second optical fiber and a polished end surface of the first optical fiber is caused to abut against a polished end surface of the second optical fiber. In many cases, a ferrule is applied to the end of each of the fibers. A coupling member receives the ferrules from opposite sides and ensures that the two fibers are axially aligned and that their end surfaces abut against each other. Examples of such connectors are disclosed in U.S. Pat. Nos. 4,167,303 and 4,477,146.
In recent years, optical fiber connectors of a different sort have been developed for optically coupling one optical fiber to another. These newer connectors align two or more optical fibers in a side-by-side relationship and employ a mirror to couple optically the output from one optical fiber to one or more other parallel optical fibers. U.S. Pat. No. 4,167,303, commonly assigned with the present application, discloses an optical fiber splice terminal which includes a housing assembly to receive prepared end sections of two optical fibers in a common input section. The housing assembly holds both optical fibers securely in an aligned side-by-side relationship such that the end faces are adjacent a clear optical element. The optical element includes a reflective surface of parabolic shape. Thereby, light emitted from the end face of one fiber is reflected into the end face of the other fiber in a focused beam.
In U.S. Pat. No. 4,763,978, an optical fiber connector is disclosed comprising a plurality of spaced-apart optical fiber receiving holes formed at one end of the connector, and a spherical mirror formed at an opposite end of the connector. The fiber receiving holes are disposed on opposite sides of the principal axis of the spherical mirror. When light is emitted from the end face of an optical fiber inserted into one of the holes, the light impinges on the mirror and is reflected into the end face of an optical fiber inserted into another hole symmetrically disposed with respect to the principal axis.
The optical fiber connector of U.S. Pat. No. 4,763,978 has several drawbacks. The connector of this patent is a one-piece construction. Once the fibers are inserted into their respective holes and the connector is assembled, no means are provided for disassembling the connector. For example, it may be desirable at some point to disassemble the connector and to replace the spherical mirror with one of different reflectivity to attenuate the emitted light. Thus, the one-piece construction limits the flexibility of the connector. Moreover, no special means are provided to prevent skewing of the fibers inserted into the holes. Thus, the side-by-side fibers may become misaligned with respect to each other and with respect to the principal axis.
Other patents which disclose devices that use a mirror to optically couple the output from side-by-side optical fibers include the following U.S. Pat. Nos. 3,883,223; 4,274,706; 4,329,017; 4,583,820; 4,675,860; 4,703,472; and 4,722,582.